Northern Gannet, Morus bassanus

Northern
Gannets are cold-water sulids, the family that includes the more
warm-water-inclined boobies; they are found in the North Atlantic and
the Eurasian shore of the Arctic Ocean. This one, present since 2012 at
the Farallons where I took this picture in 2014, and also seen
occasionally in San Francisco Bay, is the only one of its species ever
reported in the Pacific Ocean. It is believed to have crossed from the
Atlantic by way of the Northwest Passage, recently subject to thaw as a
result of climate change. The bird has engaged in nest-building (as
here) and other attempts to attract a mate that, sadly, are
unlikely ever to meet with success. Its sex is not known.